NSFW warning for profile image, background images and links

[trymeouteh]

Please add a setting to check off weather a profile image is NSFW, background image is NSFW which will prompt the user with a message on weather to view the background image or not.

Also add a NSFW checkbox next to every link which will show a NSFW icon next to them. When a user clicks on a NSFW link, they will be warned before proceeding.

This is useful for instances who want to host NSFW content but have it blocked by default unless the user alllows it. This will prevent any "unwanted surprises" such as seeing a nude background image or click on a link to an adult site.